2. minifs
------------
This appears a mini-linux system that operates as a second stage
bootloader or at least as a maintainance tool. It lives in the /dev/
mtd3 partition.
It is not clear if it contains its own kernel or shares the kernel
with the real system.
Download: http://www.trendtac.nl/documents/Recovery_EPC700.zip (this
includes also a certain version of a recovery.img for 4.)
I guess (since I could neither find code in U-Boot nor the Kernel -
and one can't overwrite a rootfs while it is being used) the
function of this minifs is to show the penguin picture, and check
for F3 to flash a root-filesystem. And, boot the final system if F3
is not pressed.
To get this minifs into flash through U-Boot, one has to press fn
+leftshift+rightshift and have minifs.img (this is a .jffs2) on a
FAT-SD card (does not work on my broken device - or the kernel in
flash does not work any more).
I have followed (mostly) the instructions at http://members.home.nl/janrinze/trendtac.html#Hacking_the_root_filing_system
: and got an excerpt of the minifs.
Key findings:
* it is indeed a "Mini-Linux" rootfs
* without kernel (so it shares the kernel with the production system -
which must e.g. support jffs2)
* uses busybox
* has a directory /wkw_sh which contains the recovery menus (which use
clear, echo, read etc. to communicate with the user)
* it reads the Ethernet Mac address from the MAC partition
* it looks for a "Recovery*.img"
* recovery (reflashing) is handled by /wkw_sh/recovery.sh
* it optionally formats (eraseall) /dev/mtdnand (which must IMHO be
provided by the kernel initialization?)
* it mounts /dev/nand to /mnt/target
* it does a tar jxf to /mnt/target
* I could not find a reference to the *.rec format for Letux 400
recovery (Note: the machine I have analysed appears to be older than
the standard Letux 400)
* a setup_system.sh script appears to wget the full system from some
internet server
* the server is identified through an obscure getserver command built
into busybox
* some scripts write to echo 0 > /proc/jz/numlock_led, echo 0 > /proc/
jz/capslock_led, echo 0 > /proc/jz/eth0_led, echo 1 > /proc/jz/
numlock_led etc. So we should provide them in the 2.6 kernel
* /etc/inittab is configured to run the /etc/init.d/start scropt on tty0
What does this mean for our Kernel 2.6?
1. we can't simply flash the kernel into NAND - we will most likely
the recovery function (that may be the issue on my machine that I now
have a 2.6 kernel without jffs2 support in the kernel partition)
2. we can either make the kernel compatible to the minifs or
3. develop our own minifs compatible to the kernel
BR,
Nikolaus
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